package org.bouncycastle.util.encoders;

/**
 * Converters for going from hex to binary and back.
 * <p>
 * Note: this class assumes ASCII processing.
 */
public class Hex {
    private static HexTranslator encoder = new HexTranslator();

    private static final byte[] hexTable = { (byte) '0', (byte) '1', (byte) '2', (byte) '3', (byte) '4', (byte) '5', (byte) '6', (byte) '7',
            (byte) '8', (byte) '9', (byte) 'a', (byte) 'b', (byte) 'c', (byte) 'd', (byte) 'e', (byte) 'f' };

    public static byte[] encode(byte[] array) {
        return encode(array, 0, array.length);
    }

    public static byte[] encode(byte[] array, int off, int length) {
        byte[] enc = new byte[length * 2];

        encoder.encode(array, off, length, enc, 0);

        return enc;
    }

    public static byte[] decode(String string) {
        byte[] bytes = new byte[string.length() / 2];
        String buf = string.toLowerCase();

        for (int i = 0; i < buf.length(); i += 2) {
            char left = buf.charAt(i);
            char right = buf.charAt(i + 1);
            int index = i / 2;

            if (left < 'a') {
                bytes[index] = (byte) ((left - '0') << 4);
            } else {
                bytes[index] = (byte) ((left - 'a' + 10) << 4);
            }
            if (right < 'a') {
                bytes[index] += (byte) (right - '0');
            } else {
                bytes[index] += (byte) (right - 'a' + 10);
            }
        }

        return bytes;
    }

    public static byte[] decode(byte[] array) {
        byte[] bytes = new byte[array.length / 2];

        encoder.decode(array, 0, array.length, bytes, 0);

        return bytes;
    }
}
